Added a separate agent for using pattern miner without OAC.
Added a separate Atomspace for loading clean test corpus.
Fixed a bug in CMakelist file for pattern miner.
Added the necessary pre-load scm files into corpus Atomspace.
Merge branch 'master' of http://github.com/opencog/opencog into PM
Comment out the pre-load Pattern Miner corpus scm file in embodiment default conf file.
Merge branch 'master' of http://github.com/opencog/opencog into PM
Merge branch 'master' of http://github.com/opencog/opencog into PM
added a customized Atom2String function to make keystring for unified pattern.
Fixed sorting patterns and extra the first gram patterns.
Fixed bugs in find all instances for a pattern.
Fixed variable map problems.
Fixed a bug for avoiding extending a existing link to a pattern .
Removed patternVarMap from HTreeNode again.
Fixed using the right nodes to extend next gram patterns.
Merge pull request #761 from shujingke/PM

Debug on pattern miner.
Replace pet by avatar is some log
Simplify loop (C++11 style)